Gravity actuated switch



2 Sheets-Sheet 1 L. L. RICE GRAVITY ACTUATED s'wl'rcu Filed April 30, 1943 Aug. 28, 1945.

Aug. 28, 1945. L l.. RICE GRAVITY ACTUATED SWITCH Filed April 30, 1943` 2 Sheets-Sheet 2 10 l/ /la Patented ug. k28, 1945 I GRAVITY ACTUATED SWITCH Livingston L. Bice, Nashville, Tenn., asslgnor to Consolidated Vulteelrorait Corporation, San Diego, Calif., a corporation of Delaware Application April 30, 1943, Serial No. 485,098

v 7 Claims. y(Cl. 200-52) The invention relates generally to switches and more' particularly to a gravity controlled switch.

One object of the invention is to provide a gravity controlled switch of new and improved construction, reliable. in operation. easily repaired and serviced, and reasonable in cost of manufacture.

'Another object is to provide a. gravity controlled switch that possesses a high degree of sensitivity yet is not affected by vibration or similar adverse conditions to which it may be subjected.

A further object isto provide a gravity controlled switch that is consistent in its response and positive in its operation.

Other objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. i is a front elevational view of a switch embodying the features of my invention, with an external cover partially broken away to reveal a sub-cover.

Fig. 2 is a horizontal section taken approximately along the line 2-2 oi' Fig. l.

Fig. 3 is a fragmentary and slightly enlarged perspective view showing the interlocking ends of the armatures in a position opposite to that shown in Fig. 2.

Fig. 4 is a partially diagrammatic view showing the wiring of the switch. The view is taken in the same direction as Fig. 1 with a portion of the switch shifted vertically. better to show the wiring connecting it to the remaining portion of the switch.

While the invention is susceptiblel of various modifications and alternative constructions, it is here shown and will hereinafter be described 'in a preferred embodiment. It is not intended. however, that the invention is to be limited thereby to the speciilc disclosure made. 4Ori the contrary, it is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention as detlned in the appended claims.

As shown in the drawings for purposes of disclosure, the switch comprises generally a positional and hence gravity responsive means, generally designated I0, and translating or multiplying means, generally designated` Il, associated with and controlled by the means Il. The gravity responsive means Il comprises a tubular member I2 which herein is a straight cylindrical tube approximately three inches long and .750 ot an inch in outside diameter, withwalls initially one-sixteenth of an inch thick. Within the tubular member I2 is a solid element Il movable, under the influence of gravity and with a change in position oi the tubular member ,I2 relative' to the horizontal, from end to end of the tubular member. Herein the solid element Il takes the form of a ball to increase the sensitivity oi' the gravity .responsive means. Though the tubular member I2 and the ball Il are both preferably made of bronze or brass, the interior o f the tube and the lball are each given a silver plating 0.0005 oi' an inch thick in order to enhance the electrical conductivity of the parts.

Each end of the tubular member I2 is closed by a spool Il of an insulating material having at one end a radially outwardly extending flange Il with an outside diameter equal to the outside diameter of the tube i2. Each spool is held in place closing an end of the tube I2 by a knurled conduitnut Il having a radially inwardly extendingnange I1 overlying the-flange IB oi the spool I4 when the parts arein position. To receive the conduit nuts, each end of the tubular member I2 is formed with external threads Il. Disposed at each end of the tubular'member I2 and supported centrally oi the member, and in spaced, insulated relation thereto is an'electrical contact Il preferably of brass and also silver plated 0.0005 of an inch. The contact is tor con- .venience formed from a commercial hex-head bolt 2l -mounted with itshead on the inner side of the spool Il to form the contact Il and projecting outwardly through a central bore 2i formed inthe spool. A nut 22 secures the contact in the spool and the projecting portion of the bolt 20 provides a convenient place for the attachment of a lead wire.

Before the interior of the tubular member I2 is silver plated, as above stated. it is reamed to an exact inside diameter of .634 of an inch. The

ball II is made to an exact initial diameter ot f five-eighths ot an inch so that with the silver plating the total diameter of the ball is .626 o! an inch. It will thus be seen that in the finished means there will be a clearance of but .007 oi an inch between the ball and the tube. 'lhis close nt between the ball and the tube is provided in order to attain some degree of damping eil'ect by the air in the tube as the ball rolls from end to end thereof. In order that this eilect may not be too great, a vent passage 2l isprovided in each spool I4. These'vent holes, by allowing circulation o! air. serve the further purpose of preventing condensation which would interiere with the functioning of the switch. It is believed apparent from ,the above that the means III will be sensitive and positive in its action, due to the weight and shape of the element I3, while at the same time it will not be ail'ected by vibration or other conditions to which it may be subjected as are the switches of the prior art. 'I'his means, moreover, is equally operative whether in normal or inverted position, thus adapting it particularly well for use in aeroplanes where flight sometimes is upside down.

The translating means |I, i'or which the gravity responsive means I acts as an exciter or controller, comprises generally a pair of electrically energized devices which herein preferably take the form of relays, generally designated 26 and 26. 'I'he relay 26 comprises an energizing coil 21 and a pivoted amature 23 biased to a normal position by a tension spring 26. The armature 26 is operatively associated with a 'pair of leaf elements 30 and 3| forming the movable contacts, respectively, of switches 32 and 33. The stationary contacts 34 and 36 of the switches 32 and 33, respectively; are formed by brackets upstanding from a base B upon which the relays 26 and 26 are mounted. The contact 34 overlies the contact 30, while the contact 36 underlies the contact 3|, so that the switch 32 is closed when the armature 23 is in normal position and open when the armature is in actuated position, while just the converse is true for the switch 33. The contacts 34 and 36 are at their point of attachment, to the base B provided with terminals 36 and 31, respectively, and contacts 30 and 3| are likewise at their point oi' attachment to the base provided with -terminals 33 and 36, respectively.

The relay 26 is similar to the relay 26 and comprises a coll 42 and a pivotally mounted armature 43 biased by a tension spring 44 to a normal position. This relay controls but a single switch 45, the stationary contact 46 ot which is formed by a bracket upstanding from the base B, while the movable contact 41 is carried by the armature 43. The stationary contact 46 is at its point of mounting on the base B provided with a terminal 48, while the movable contact 41 is through a ilexible lead 49 connected to a terminal 60 on the base.

The relays are provided with a mechanical interlock whereby the relays are mutually operative to retain one or the other of the armatures of the relays in actuated position, even though both relays are deenergized. Such a mechanical interlock is herein eil'ected in a simple and expeditious manner by the armatures of the relays. To that end, the relays are mounted at right angles to one another with the relay 26 herein mounted with the axis of its coil at right angles to the base B and the relay 26 mounted with the axis of its coil parallel to the base B. As clearly seen from Fig. 2, the free end 26' o! armature 28 in its normal position overlies the free end 43 of the armature 43 when in its actuated position. However, when the armature 23 is moved to its actuated position it clears the amature 43 and permits the same to be returned to normal position under the influence of its spring 44, as shown in Fig. 3. Conversely, as clearly seen from Fig. 3, the free end of the armature 43 in normal position overlies and retains the armature 28 in actuated position and again clears the armature 28 and permits it to return to its normal position when the armature 43 is attracted by the coil 42.

As best seen in Fig. 4. the gravity actuated exciter or control means I6 is connected to the means |I in a manner to energize one or the other oi the relays, depending upon which end of the tubular member I2 the ball I3 is in. To that end, a. lead 66 connects the right hand contact I6, as viewed in Fig. 4, to the terminal 31, while a lead 66 connects the left hand contact I6 to the terminal 43. Terminal 33 is by lead 61 connected to a terminal 6I and terminal 60 is by a lead 66 connected to a terminal 60. The wiring is completed by connecting the ends ci the coil 21 tc the terminals 36 and 40 and the ends of the coil 42 to the terminals 36 and 63. It is believed apparent from the foregoing that the switch 32 constitutes the mainswitch to be controlled, while the switch v33 is disposed in the energizing circuit for the coil 42 and the'switch 46 is Adisposed in the energizing circuit for the coil 21. At times it may prove desirable to have leads 6I and 32, running respectively from the terminals 36 and 3l to terminals 63 and I4, mounted on a separate base 66 for positioning on the outsideot a casina or housing In which the mechanism so tar described may be enclose (see Figs. 1 and 2).

Herein the switch is disclosed as housed in a casing 10 which includes a sub or interior cover 1I and an external cover 12. The external cover 12 is secured by spring clips 13 for ready removal or replacement. while the interior or sub-cover 1I is more permanently secured as by means oi bolts 14. The sub-cover forms a support on which the tubular member I2 is adjustably mounted lthrough the medium oi 'a channel shaped, clamp-like holder 16. The holder 16 is somewhat longer than the tubular member I2 and is near one end pivotally connected as by means o! a rivet 16 to the sub-cover 1I. The other end of the holder carries a screw 11 which projects outwardly through an arcuate slot 13 formed on the sub-cover 1I and centered on the rivet 16. Also formed in the sub-cover 1I radially inwardly oi the slot 13 is a second arcuate slot 13 also centered on the rivet 16. Placed on the holder 16 to be visible through the slot 13 is a marking III, while on the sub-cover between the arcuate slots is a scale 3| by which the angular position of the tubular member I2 may be determined. By loosening the screw 11 the tubular member I2 is readily and conveniently adjusted to iorm any desired angle with the horizontal and the same may then be secured in that adjustment by tightening the screw 11. Base B is secured to the bottom or casing 13 by sui-table bolts. l

The switch mechanism above described has, of course, a variety of applications and is particularly adapted ior use in conjunction with some member, vehicle or the like which is either to be maintained in some position relative to the horizontal, or to initiate or arrest operation of some related device when the member or vehicle with which the switch is associated departs from s predetermined or desired position. By way oi example, the switch may be employed in an aeroplane for the purpose of controlling a pump, control rudder, or the like, when, for example, the nose of the aeroplane drops a predetermined number of degrees below the horizontal. Let it be assumed, therefore, for the purpose oi describing the operation of the switch that the same is to be employed in conjunction with an aeroplane. Under those circumstances. the unit is attached in the position shown in Fig. 1

and with the right hand end of the unit. as

.viewed in Fig. l, directed toward the nose of the aeroplane. As a result, the gravity responsive means I8 assumes a, position generally parallel with the longitudinal center line of the aeroplane and also generally horizontal. With the entire unit/attached by securing Vthe casing 18. f

give to the tubular member I2 the exact position which will result in operation of -the pump or the like when the nose of the plane drops the predetermined number of degrees below the horizontal.

Under the lconditions above assumed, and with the plane in horizontal ilight or climbing, the

yright hand end of the tubular member I2, as

viewed in Figs. 1 and 4, will be higher than the left hand end and hence the ball I3 will occupy its terminal position at'the left end of the tube, that is, in the position shown in Figs. 1 and 4, namely. in contact with the left one of the contacts I9. 'I'his will complete an energizing circuit for the coil 21 of relay 25. This circuit may be traced as follows: From the terminal 38 which is intended to be connected to the positive side of a battery through coil 21, terminal 80, lead 59 terminal 50, lead 43. switch 45, terminal 48, lead 58, contact I9, ball I3, and tubular member I2 which is grounded. Switch 48 was closed because through the mechanical interlock between the two relays armature 28 of relay 23 was holding armature 43 in actuated position even though coil 42 was not energized. With the energization of coil 21, armature 28 is, of course, actuated thereby, first of all, opening switch 32 to break the circuit to the pump or other device controlled by the switch 32. At the same time switch 33 is closed to condition' a circuit for the energization of the coil 42 at such time that the ball I3 is by change in position of the tubular member I2 caused to engage theright hand contact I3. Also at the'same time this movement of .the armature 28 to actuated position moves it out of its interlocking relation to the armature 43 and thereby renders that armature free to return to its normal position under the iziiluence of the spring 44 so long as the coil 42 is not energized. So long as the ball I3 does not engage the right hand contact I9, coil 42 is deenergized and hence the armature 43 now moves into interlocking relationship to the armature 28. The amature 28 thus is held in actuated position and the switches 32 and 33 remain open and closed, respectively. even though the coil 21 is deenergized by opening of the switch 48 which takes place as an incident to returnof the armature 43 to its normal position. It will be appreciated that the armature 43 passes into interlocking relationship with lthe armature 28 before the switch 48 is opened.

Should now the nose of the aeroplane drop more than the predetermined amount, the ball I3 will roll to the right and make engagement with the right hand contact I3 to complete the previously conditioned energizing circuit for the coil 42. This circuit may be traced from terminal 33 through coil 42, lead l1, switch 33 which,

as previously stated, is now closed, lead 88, right hand terminal I8, ball I3, and tubular member I2 which is at ground potential. With the energization of the coil 42 the armature 43 is attracted to actuated position, thereby releasing armature 28 for return to its normal position. With such return the switch 22 is closed to complete the circuit to be controlled, namely, the circuit to the pump or other device initiating operation thereof. At the same time. switch 33 is opened to break the circuit to the coil 42 but, of course, the armature 43 remains in actuated position because, the' armature 28 had previously moved into interlocking relation with the armature 43. The switch 45 is again closed to condition the energizing circuit for the coil 21. When the plane again returns to horizontal flight, ball I3 will, of course, return to the left end of the tubular member I2 and the relays will assume the condition initially described, thereby arresting operation of the pump or other device initiated by closure of the switch 32.

I claim:

l. In a, gravityl controlled switch, a straight tubular member, an element responsive to gravity mounted within said member and movable 1ongitudinally thereof as said member changes position relative to the horizontal, said element` j conforming in transverse cross section to the transverse cross section of the space within said member and having a maximum cross sectional area slightly less than the cross sectional area f of the space within said member whereby pneumatically to retard longitudinal movement of the element within the member, and means forming an electrical contact supported on and electrically insulated from said tubular member,

at an end thereof, in position to be engaged by said element when at said end. y

2. In a gravity controlled switch, a straight tubular member closed at each end, an element responsive to gravity mounted within said member and movable longitudinally thereof as said member changes position relative to the horizontal, said element conforming in transverse cross section to the transverse cross section of the space within said member and having a maximum cross sectional area slightly less than the cr'oss sectional area of the space within said member, an electrical contact mounted at an end of said member in position to be engaged by said element when the same is at said end of the member, and a bleed opening in said. tubular member near each end thereof whereby to allow longitudinal movement of the element, in the tubular memaber, toward and away fromsaid contact, at a pneumatically retarded rate.

3. In a gravity controlled switch, a member comprising electrically conducting material and having a, channel therein of uniform sectional size and shape throughout said channel, an electrical contact carried by said member in insuhaving a channel therein of uniform sectional size and shape, an electrical contact carried by said member in insulated relation thereto, said contact Ibeing exposed in said channel, and a. solid electrically conductive element mounted within said member and movable, under the influence of gravity as the member changes position relative to the horizontal, longitudinally of said member into and out of engagement with said contact, the surfaces of said member defining said channel, the surfaces oi' said conductive element and of said contact being coated with a layer od high electrical conductivity, whereby said conductive element forms a movable switch element electrically connecting said member with said contact when said element engages the contact.

5. In a gravity controlled switch, \a straight tubular member having a cylindrical interior space closed at each end, a ball mounted within said member and rollwble longitudinally thereof as said member changes position with respect to the horizontal, the external and internal surfaces at least of said ball and of said member respectively being electrically conductive, said ball and the internal surface of said member having a clearance only of the order of .007 of an inch whereby the air in said member serves slightly to damp the movements of said ball, an electrical contact extending into said tubular member in insulated relation thereto in position to be contacted by said ball while in electrical contact with said member, and a bleed opening in said tubular member near each end thereof.

6. In a gravity controlled switch a member comprising electrically conducting material and having achannel therein of uniform sectional size and shape. a ball mounted in said channel and rollable longitudinally thereof as said member changes position with respect to the horizontal, the surfaces of said ball and channel being electrically conductive and the clearance area surrounding the ball within the channel being of the order of less than 3% of the sectional area of the channel whereby the air in said channel serves to retard movement of said ball longitudinally of the channel, and an electrical contact exposed in said channel at an end thereof and in insulated relation with respect to said member in position to be engaged by said ball while in electrical contact with said member.

7. In a gravity controlled switch. a length of cylindrical metal pipe externally threaded at its opposite ends, plugs of electrically insulating material closing the opposite ends of said pipe, collars threadedly engaging the ends of said pipe to hold said plugs in place, studs of electrically `conducting material extending axially in said plugs and having heads exposed in the pipe inwardly of the plugs and portions exposed outwardly thereof, and a ball having surfaces of electrically conducting material within said pipe and rolls-ble therein to engage either of said studs by tilting the pipe, said pipe being accurately sized to snugly enclose said ball with sufll-v cient clearance to allow the ball to roll within the pipe at a pneumatically retarded rate.

LIVINGSTON L. RICE. 

